Composite vehicle body

ABSTRACT

A vehicle body may have an internal skeleton, and a skin fabricated in-situ over the internal skeleton. The internal skeleton may be fabricated via a first additive manufacturing system. The skin may be fabricated via a second additive manufacturing system that is different from the first additive manufacturing system.

RELATED APPLICATIONS

This application is based on and claims the benefit of priority fromU.S. Provisional Application No. 62/417,056 that was filed on Nov. 3,2016, the contents of which are expressly incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates generally to a vehicle body and, moreparticularly, to a vehicle body made from a composite material.

BACKGROUND

A vehicle body (e.g., an airplane body, a car body, or a boat body)generally includes an internal skeleton that gives shape to the vehicle,and a skin that overlays the skeleton and provides a smooth outersurface. Modern vehicle bodies are fabricated from a combination ofdifferent materials, including composites. For example, the skeleton istypically made of wood, aluminum, or stainless steel, while the skin istypically made of a fiber (e.g., a carbon fiber or fiberglass) embeddedwithin a resin matrix.

Pultrusion is a common way to manufacture straight skeletal parts of avehicle body (e.g., beams, longerons, etc.). During pultrusionmanufacturing, individual fiber strands, braids of strands, and/or wovenfabrics are pulled from corresponding spools through a resin bath andthrough a stationary die. The resin is then allowed to cure and harden.Due to the pulling of the fibers prior to curing, some of the fibers mayretain a level of tensile stress after curing is complete. This tensilestress can increase a strength of the skeletal part in the direction inwhich the fibers were pulled.

A vacuum-assisted resin transfer molding (VARTM) process is commonlyused to fabricate the skin of the vehicle body, after the internalskeleton has already been formed. In a VARTM process, sheets of fibrousmaterial are manually pulled over the internal skeleton and then tackedin place. The tacked material is then manually coated with a liquidmatrix (e.g., a thermoset resin or a heated thermoplastic), covered witha vacuum bag to facilitate impregnation of the liquid matrix, andallowed to cure and harden.

Although pultrusion manufacturing and VARTM can be an acceptable ways toproduce vehicle body parts in some situations, they can also beproblematic. In particular, the VARTM-produced skin is often attached tothe pultruded skeletal parts and/or reinforced via metallic fasteners(e.g., screws, rivets, and clips). The use of metallic fasteners candrive skeletal design and increase a weight and cost of the vehiclebody. In addition, the various vehicle body parts may need to be joinedto each other via specially designed hardware, which can also be heavyand costly. Further, electronics (e.g., sensors, heaters, electricalleads, etc.) may need to be added to the vehicle bodies aftermanufacture, which can further increase the weight, cost, andunreliability. Finally, conventional pultrusion and VARTM manufacturingprocesses may provide little flexibility in the design and/or use of thevehicle body.

The disclosed composite vehicle body is directed to overcoming one ormore of the problems set forth above and/or other problems of the priorart.

SUMMARY

In one aspect, the present disclosure is directed to a vehicle body. Thevehicle body may include an internal skeleton, and a skin fabricatedin-situ over the internal skeleton. The internal skeleton may befabricated via a first additive manufacturing system. The skin may befabricated via a second additive manufacturing system that is differentfrom the first additive manufacturing system.

In another aspect, the present disclosure is directed to another vehiclebody. This vehicle body may include an internal skeleton having aplurality of adjacent hollow tubes extending in a length direction ofthe wing and being formed from a plurality of continuous fibers coatedwith a matrix. The vehicle body may also include a skin having aplurality of continuous fibers coated with a matrix and laid over theinternal skeleton. The plurality of continuous fibers of both theinternal skeleton and the skin may be in tension, and at least one ofthe plurality of adjacent hollow tubes may be coated to function as atleast one of a fuel tank and a fuel passage.

In another aspect, the present disclosure is directed to a method offabricating a vehicle body. The method may include implementing a firstadditive manufacturing technique to fabricate an internal skeleton fromcontinuous fibers coated with a matrix. The method may also includeimplementing a second additive manufacturing technique to fabricate askin over the internal skeleton from continuous fibers coated with amatrix.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of an exemplary vehicle body;

FIG. 2-5 are diagrammatic illustrations of exemplary portions of thevehicle body of FIG. 1 during manufacture;

FIG. 6 is a cross-sectional illustration of an exemplary fiber that maybe used to fabricate the vehicle body of FIG. 1; and

FIGS. 7 and 8 are diagrammatic illustrations of additional exemplaryportions of the vehicle body of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary vehicle body (“body”) 10. In thedisclosed embodiment, body 10 is an aircraft body (e.g., an airplanebody or a drone body). It is contemplated, however, that body 10 couldbe of another type (e.g., a car body, a boat body, etc.), if desired.Body 10, regardless of its configuration and intended use, may includeone or more components (e.g., a fuselage 12, one or more wings 14, etc.)made from an internal skeleton (e.g., spars, ribs, stringers, bulkheads,trusses, longerons, etc.) 16 covered by an external skin 18. In someembodiments, the components of body 10 may be fabricated separately andsubsequently joined together (e.g., via threaded fastening, riveting,etc.). In other embodiments, the body components may be fabricatedtogether as an integral monolithic structure (e.g., a structure thatcannot be disassembled without at least some destruction).

As shown in FIG. 2, one or more of the components of body 10 may befabricated via an additive manufacturing process. For example, skeleton16 may be fabricated from a first additive manufacturing process, whileskin 18 may be manufactured from a second and different additivemanufacturing process. It is contemplated that both skeleton 16 and skin18 could be manufactured from the same additive manufacturing process,if desired.

The first additive manufacturing process may be a pultrusion and/orextrusion process that creates hollow tubular structures 20 from acomposite material (e.g., a material having a matrix M and at least onecontinuous fiber F). In particular, one or more heads 22 may be coupledto a support 24 (e.g., to a robotic arm) that is capable of movinghead(s) 22 in multiple directions during discharge of structures 20,such that resulting longitudinal axes 26 of structures 20 arethree-dimensional. Such a head is disclosed, for example, in U.S. patentapplication Ser. Nos. 13/975,300 and 15/130,207 and in PCT ApplicationNumber 2016042909, all of which are incorporated herein in theirentireties by reference.

Head(s) 22 may be configured to receive or otherwise contain the matrixmaterial M. The matrix material M may include any type of liquid resin(e.g., a zero volatile organic compound resin) that is curable.Exemplary resins include epoxy resins, polyester resins, cationicepoxies, acrylated epoxies, urethanes, esters, thermoplastics,photopolymers, polyepoxides, thermoset acrylates, thermosets,bismaleimides, silicon, and more. In one embodiment, the pressure of thematrix material M inside of head(s) 22 may be generated by an externaldevice (e.g., an extruder or another type of pump) that is fluidlyconnected to head(s) 22 via corresponding conduits (not shown). Inanother embodiment, however, the pressure may be generated completelyinside of head(s) 22 by a similar type of device and/or simply be theresult of gravity acting on the matrix material M. In some instances,the matrix material M inside head(s) 22 may need to be kept cool and/ordark in order to inhibit premature curing; while in other instances, thematrix material M may need to be kept warm for the same reason. Ineither situation, head(s) 22 may be specially configured (e.g.,insulated, chilled, and/or warmed) to provide for these needs.

The matrix material M stored inside head(s) 22 may be used to coat anynumber of continuous fibers F and, together with the fibers F, make upwalls of composite structures 20. The fibers F may include singlestrands, a tow or roving of several strands, or a weave of many strands.The strands may include, for example, carbon fibers, vegetable fibers,wood fibers, mineral fibers, glass fibers, metallic wires, SiC Ceramicfibers, basalt fibers, etc. The fibers F may be coated with the matrixmaterial M while the fibers F are inside head(s) 22, while the fibers Fare being passed to head(s) 22, and/or while the fibers F aredischarging from head(s) 22, as desired. In some embodiments, a fillermaterial (e.g., chopped fibers) may be mixed with the matrix material Mbefore and/or after the matrix material M coats the fibers F. The matrixmaterial, the dry fibers, fibers already coated with the matrix materialM, and/or the filler may be transported into head(s) 22 in any mannerapparent to one skilled in the art. The matrix-coated fibers F may thenpass over a centralized diverter (not shown) located at a mouth ofhead(s) 22, where the resin is caused to cure (e.g., from theinside-out, from the outside-in, or both) by way of one or more cureenhancers (e.g., UV lights and/or ultrasonic emitters) 27.

In the example of FIG. 2, structures 20 extend in a length direction ofwing 14 and makeup at least a portion of skeleton 16. Each structure 20may be discharged adjacent another structure 20 and/or overlap apreviously discharged structure 20, and subsequently cured such that theliquid resin within neighboring structures 20 bonds together. Any numberof structures 20 may be grouped together and have any trajectoryrequired to generate the desired skeletal shape of wing 14.

In some embodiments, a fill material (e.g., an insulator, a conductor,an optic, a surface finish, etc.) could be deposited inside and/oroutside of structures 20 while structures 20 are being formed. Forexample, a hollow shaft (not shown) could extend through a center ofand/or over any of the associated head(s) 22. A supply of material(e.g., a liquid supply, a foam supply, a solid supply, a gas supply,etc.) could then be connected with an end of the hollow shaft, and thematerial forced through the hollow shaft and onto particular surfaces(i.e., interior and/or exterior surfaces) of structure 20. It iscontemplated that the same cure enhancer(s) 27 used to cure structure 20could also be used to cure the fill material, if desired, or thatadditional dedicated cure enhancer(s) (not shown) could be used for thispurpose. The fill materials could allow one or more of structures 20 tofunction as fuel tanks, fuel passages, electrical conduits, ventilationducts, etc.

The second additive manufacturing process used to fabricate theexemplary wing 14 of FIG. 2 may also be a pultrusion and/or extrusionprocess. However, instead of creating hollow tubular structures 20, thesecond additive manufacturing process may be used to discharge tracks,ribbons, and/or sheets of composite material over tubular structures 20(and/or over other features of skeleton 16) to thereby fabricate skin18. In particular, one or more heads 28 may be coupled to a support 30(e.g., to an overhead gantry) that is capable of moving head(s) 28 inmultiple directions during fabrication of skin 18, such that resultingcontours of skin 18 are three-dimensional.

Head 28 may be similar to head 22 and configured to receive or otherwisecontain a matrix material M (e.g., the same matrix material M containedwithin head 22). The matrix material M stored inside head(s) 28 may beused to coat any number of separate fibers F, allowing the fibers F tomake up centralized reinforcements of the discharging tracks, ribbons,and/or sheets. The fibers F may include single strands, a tow or rovingof several strands, or a weave of multiple strands. The strands mayinclude, for example, carbon fibers, vegetable fibers, wood fibers,mineral fibers, glass fibers, metallic wires, etc. The fibers F may becoated with the matrix material M while the fibers F are inside head(s)28, while the fibers F are being passed to head(s) 28, and/or while thefibers F are discharging from head(s) 28, as desired. The matrixmaterial, the dry fibers, and/or fibers already coated with the matrixmaterial may be transported into head(s) 28 in any manner apparent toone skilled in the art. The matrix-coated fibers F may then pass throughone or more circular orifices, rectangular orifices, triangularorifices, or orifices of another curved or polygonal shape, where thefibers F are pressed together and the resin is caused to cure by way ofone or more cure enhancers 27.

In another exemplary embodiment shown in FIG. 3, only a single additivemanufacturing process is being used to fabricate wing 14. In particular,the second manufacturing process described above is being used toadditively build up layers of skeleton 16 (e.g., of spars and/orstringers) with continuous fibers F and matrix material M and to coverskeleton 16 with additively built up layers of skin 18 of the same ordifferent continuous fibers F and matrix material M. The fibers F makingup skeleton 16 may continue over an outer surface of skeleton 16 tobecome part of skin 18, such that a continuous mechanical connection isformed between skeleton 16 and skin 18 by the continuous fibers F. Inthis way, the number of fasteners required to connect skin 18 toskeleton 16 may be reduced (if not eliminated). It is contemplated thatsupport 24 and/or support 30 may be used to move any number of heads 28during fabrication of wing 14 (or during fabrication of any othercomponent of body 10).

As described above, the first and second additive manufacturingprocesses can be extrusion or pultrusion processes. For example,extrusion may occur when the liquid resin matrix M and the associatedcontinuous fibers F are pushed from head(s) 22 and/or head(s) 28 duringthe movement of supports 24 and/or 30. Pultrusion may occur after alength of resin-coated fibers is connected to an anchor (not shown) andcured, followed by movement of head(s) 22 and/or heads(28) away from theanchor. The movement of head(s) 22 and/or head(s) 28 away from theanchor causes the fibers F to be pulled from the respective head(s)along with the coating of the matrix material M.

In some embodiments, pultrusion may be selectively implemented togenerate tension in the fibers F that make up skeleton 16 and/or skin 18and that remains after curing. In particular, as the fibers F are beingpulled from the respective head(s), the fibers F may be caused tostretch. This stretching can create tension within the fibers F. As longas the matrix M surrounding the fibers F cures and hardens while thefibers F are stretched, at least some of this tension remains in thefibers F and functions to increase a strength of the resulting compositestructure.

Structures fabricated via conventional pultrusion methods may haveincreased strength in only a single direction (e.g., in the onedirection in which fibers were pulled through the corresponding dieprior to manual resin impregnation and curing). However, in thedisclosed embodiment, the increased strength in the skeleton 16 and/orskin 18 of body 10 (e.g., within wing 14) caused by residual tensionwithin the corresponding fibers F may be realized in the axial directionof each the fibers F. And because each fiber F could be pulled in adifferent direction when being discharged by head(s) 22 and/or 28, thetension-related strength increase may be realized in multiple (e.g.,innumerable) different directions.

Structures fabricated via conventional pultrusion methods may havestrength increased to only a single level (e.g., to a levelproportionate to an amount in which the fibrous cloth was stretched bythe pulling machine prior to manual resin impregnation and curing).However, in the disclosed embodiment, because the matrix M surroundingeach fiber F may be cured and harden immediately upon discharge, theforce pulling on the fiber F may be continuously varied along the lengthof the fiber F, such that different segments of the same fiber F arestretched by different amounts. Accordingly, the tensile stress inducedwithin each of the different segments of each fiber F may also bedifferent, resulting in a variable strength within the differentsegments of skeleton 16 and/or skin 18 of body 10. This may bebeneficial in variably loaded areas of body 10 (e.g., at theintersection of wing 14 and fuselage 12, within a center of wing 14, atthe leading edge of wing 14, etc.).

FIG. 4 illustrates an exemplary way in which the fibers F of skin 18 canbe arranged to provide for desired characteristics of wing 14. In thisexample, the fibers F are arranged organically (e.g., in the way that atree grows or in the way that blood veins are situated in the body).Specifically, the fibers F placed over structure 16 of wing 14 may beanchored at an intersection with fuselage 12 and in a general fore/aftcenter. The fibers F may then be pulled toward a distal tip of wing 14,and away from the fore/aft center (e.g., toward a leading or trailingedge of wing 14), with different fibers F extending different distancestoward the distal tip. In addition, because the discharging matrixmaterial M may cure immediately upon discharge from head 28 and bond toeither structure 16 or previously discharged layers of skin 18, movementof head 28 during discharge may be controlled to create trajectories ofthe fibers F that curve. It is contemplated that the fibers F may passcompletely around wing 14 at its distal termination point, and then bepulled back toward fuselage 12 following a mirror image of its initialtrajectory. This arrangement of organically arranged fibers may belocated at a top side of wing 14, at a lower side, and/or around across-sectional perimeter of wing 14 at multiple locations. With thisarrangement, a greater density of fibers F may exist near fuselage 12than near the distal tip of wing 14. Accordingly, wing 14 may be thickernear fuselage 12 and near the general fore/aft center, and taper towardthe distal tip and the leading and trailing edges. Other arrangementsand/or fiber distribution schemes may be employed, as desired.

In one exemplary embodiment shown in FIG. 5, some of the fibers F withinthe composite material making up one or more portions of body 10 haveunique characteristics. For example, while a majority of wing 14 maycomprise a structural type fiber F_(s) (e.g., carbon fibers, fiberglass,or Kevlar fibers), some portions of wing 14 may include another type offiber F (e.g., electrically conductive fibers F_(ec), optical fibersF_(o), shape memory fibers F_(sm), etc.). The other type of fibers F maybe selectively interwoven with the structural type fibers F_(s) atstrategic locations. For example, electrically conductive fibers F_(ec)may be located at leading edges and/or thinner portions of wing 14 andused as heating electrodes that can be connected to a power source andused to remove ice from wing 14. Alternative, electrically conductivefibers F_(ec) may be located at high-stress regions (e.g., at theintersection of wing 14 and fuselage 12) and used as strain gauges todetect loading of body 10. In a similar manner optical fibers F_(o) maybe located at high-stress regions and an energy beam passedtherethrough. As body 10 flexes, the optical fibers F_(o) may besqueezed and/or closed, thereby generating an optical feedback signalindicative of the flexing. In yet another embodiment, fibers F_(sm)fabricated from a shape memory alloy (e.g., Nitonol) may be interwovenwith the structural type fibers F_(s) and selectively energized (e.g.,via electricity or heat) to cause flexing (e.g., controlled pullingand/or pushing) of body 10 that results in a desired aerodynamicperformance (e.g., steering, orientation, elevation control, stability,drag, etc.). As shown in FIG. 6, it is contemplated that theelectrically conductive fibers F_(ec), the optical fibers F_(o), and/orthe shape memory fibers F_(sm) may be coated with another material(e.g., insulation, a strength enhancing layer, etc.), if desired. It isalso contemplated that other electrical components (e.g., resistors,capacitors, etc.) may be extruded through heads 22, 28 and/orautomatically picked-and-placed (e.g., via attachments associated withheads 22 and/or 28) during discharge of fibers F_(ec), fibers F_(o),and/or fibers F_(sm). Operation of these components and/or of fibersF_(ec), fibers F_(o), and/or fibers F_(sm) may be selectively tuned inthese instances, for example by adjusting a shape, tension, and/or sizeof the fibers.

Structures fabricated via conventional pultrusion and/or extrusionmethods may be limited in the orientation of the associated fibers. Thatis, the fibers may be generally overlapping and lie in parallel layers.However, in the embodiment illustrated in FIG. 5, because the matrix Msurrounding each fiber F may be cured and harden immediately upondischarge, the fibers F may be caused to extend into free space withoutadditional support. That is, the fibers F may not be required to lie inflat layers on top of each other. Accordingly, the fibers F making upskeleton 16 and/or skin 18 may be oriented in directions that areperpendicular to each other in three dimensions. For example, FIG. 5illustrates fibers F_(n) that extend in a direction normal to thesurface of wing 14. This may allow for interlocking of fiber layersand/or for the creation of unique (e.g., turbulence enhancing) surfacetextures.

As described above and shown in FIG. 5, body 10 may be fabricated as anintegral monolithic structure, in some embodiments. For example, wings14 may be fabricated together with (e.g., at the same time as andwithout separation from) fuselage 12. In particular, as support(s) 24and/or 30 move any number of head(s) 28 over skeleton 16 to create skin18 (referring to FIG. 2), head(s) 28 may pass from one wing 14, over orunder fuselage 12, and continue across the opposing wing 14. In thisinstance, the fibers F discharging from head(s) 28 may be continuousover wings 14 and fuselage 12. This process may be repeated any numberof times, such that millions (if not hundreds of millions) of fibers Fextend through the intersection between wings 14 and fuselage 12,thereby creating a strong mechanical connection without requiring theuse of specialized hardware and/or heavy fasteners.

In the exemplary embodiment shown in FIG. 5, the matrix M within thecomposite material making up one or more portions of body 10 has uniquecharacteristics. For example, while a majority of wing 14 may comprise astructural type matrix M_(s) (e.g., a conventional UV curable liquidresin such as an acrylated epoxy), some portions of wing 14 may includeanother type of matrix M (e.g., a pyrolized matrix M_(p), a matrix thatremains somewhat flexible M_(f), etc.). The other type of matrix M maybe selectively used to coat the fibers F at strategic locations. Forexample, the pyrolized matrix M_(p) may be fed into head 28 as head 28nears the leading edge of wing 14 and/or a nose of fuselage 12, suchthat the resulting composite material may function as a heat shield inthese areas. In another example, the flexible matrix M_(f) may be fedinto head 28 as head 28 nears the trailing edge of wing 14 (e.g., wherethe shape memory fibers F_(sm) are placed, such that the resultingcomposite material may be more flexible and selectively warped ortwisted to provide for the desired aerodynamic properties describedabove.

FIG. 7 illustrates an exemplary part 32 of skeleton 16 that may befabricated through the use of head 28 and support 30. Although depictedand described as a rib of wing 14, part 32 could be another skeletalcomponent of wing 14 and/or fuselage 12. In this example, part 32includes opposing outer support surfaces 34, opposing internal braces36, and a plurality of cross-pieces 38 that interconnect supportsurfaces 34 and/or braces 36. It should be noted that outer supportsurfaces 34 and/or internal braces 36 could have any desired shape, forexample curved, flat, stepped, etc. It is also contemplated that outersupport surfaces 34 and internal support surfaces 36 could form one ormore continuous surfaces, if desired. For example, one or more ofsupport surfaces 34 could be curved and generally tangential with one ormore of braces 36 (e.g., at a leading and/or trailing end of the rib).And although cross-pieces 38 are shown as generally straight andoriented at about 45° relative to support surfaces 34 and braces 36, itis contemplated that cross-pieces 38 could also be curved and/ororiented at another angle. It should be noted that, although sevenadjacent and nearly identical parts 32 are shown to make up thedisclosed rib, any number of the same or different parts 32 (e.g., onlyone part 32) may be used for this purpose.

Part 32 may be created following a unique tool path that allows for useof continuous fibers and provides for high-strength in a low-weightconfiguration. In particular, part 32 may be fabricated using amiddle-out strategy. FIG. 8 illustrates use of this strategy duringfabrication using multiple different and overlapping layers.

For example, in a first layer, head 28 may be controlled to startdischarging and curing one or more continuous resin-coated fibers at alower-left corner (e.g., adjacent an internal intersection of a lowersupport surface 34 and a left brace 36), and continue discharging andcuring the same resin-coated fiber(s) during travel upward to anadjacent upper-left corner. Head 28 may then move diagonally inwardtoward a general center of part 32, and then double back prior toreaching the center to move toward the upper-left corner following agenerally parallel trajectory. During this doubling-back maneuver, head28 may be spaced apart a distance from its original trajectory (e.g.,spaced more toward the right of part 32), such that an empty space willexist along a diagonal of part 32 and a box shape is formed at internalends of the diagonal parallel tracks. Head 28 may then move rightward toan upper-right corner of part 32, followed by about a 90° turn downwardupon reaching an internal edge of part 32. The same general pattern maybe repeated at the lower-right corner of part 32 that was made at theupper-left corner, such that a mirror image across a virtual diagonaldividing line is created. Head 28 may then move leftward and stop shortof its starting point, after which head 28 may turn through about 45°clockwise and travel diagonally completely across part 32 to theupper-right corner. Head 28 may then double back toward the lower-leftcorner along a spaced-apart parallel track, such that head 28 is nearits starting point (e.g., radially outward and slightly lower than thestarting point). During this doubling-back maneuver, head 28 may bespaced apart a distance from its original trajectory (e.g., spaced moretoward the left of part 32), such that an empty space will exist along adiagonal of part 32. As head 28 moves towards the upper-right corner, itmay deviate from its trajectory at a turn-around point and head into thecorner, such that an arrow-head shape is formed at internal ends of theparallel tracks. The arrow-head shape may bond to the hardened fiberslaid down previously at this corner location. The diagonally laidfiber(s) may bond to the box shape previously laid down at the center ofpart 32. The entire process may be repeated any number of times to add acorresponding number of material tracks to the first layer and therebyincrease a cross-sectional area of the first layer. During repetition,part 32 may grow outward and the empty spaces described above as beinglocated between the parallel tracks may be filled in. It should be notedthat, during formation of any one layer, the fibers discharging fromhead 28 may not overlap other fibers such that all fibers are laid downwithin the same plane. When head 28 reaches an endpoint of a particularlayer, the fiber(s) may be cut from head 28, such that head 28 may berepositioned for start of a new layer.

A second layer may be formed directly on top of the first layer, forexample by rotating the pattern of the first layer through a desiredangle (e.g., through about 90°). By rotating the pattern through about90°, the fibers extending diagonally completely across part 32 in thesecond layer may overlap the fibers that doubled back at the center ofpart 32 in the first layer. This overlapping of different portions ofthe repeating pattern may help to increase a strength of part 32. It iscontemplated that any number of fibers may be deposited at any locationand oriented generally normal to the overlapping layers (e.g., fibersF_(n) like those shown in FIG. 5) to interlock the layers, if desired.Additionally or alternatively, discharged but uncured portions of aprevious layer could be wrapped over subsequently formed layers and thencured to improve an interlock strength.

Any number of additional layers may be formed on top of the first twolayers in alternating orientations and/or in orientations of incrementalrotating angles (e.g., when the angle is not a multiple of 90°). Thismay continue until a desired thickness of part 32 is achieved. In oneexample, an entire fuselage 12 and/or wing 14 could be fabricated inthis manner. For example, skin 18 could be simultaneously fabricatedover part 32 when using the middle-out approach. In particular, an emptyspace may be created inside of fuselage 12 and/or wing 14 and betweenadjacent parts 32, by only creating outer portions of supports 34 and/orbraces 36.

INDUSTRIAL APPLICABILITY

The disclosed arrangements and designs of skeleton 16 and skin 18 may beused in connection with any type of vehicle body 10. For example,skeleton 16 and skin 18 may be used in connection with an airplane body,a drone body, a car body, a boat body, or any other type of vehicle bodywhere light-weight, low-cost, and high-performance are important.Vehicle body 10 may be light-weight and low-cost due to the reduction inthe number of fasteners required to secure skin 18 to skeleton 16 and/orto secure components of vehicle body 10 to each other. In addition,vehicle body 10 may be light-weight do to the use of composite materialsused to make both of skeleton 16 and skin 18. The high-performance maybe provided in the unique ways that particular fibers and resins areused and laid out within skeleton 16 and skin 18.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed vehicle body.Other embodiments will be apparent to those skilled in the art fromconsideration of the specification and practice of the disclosed vehiclebody. It is intended that the specification and examples be consideredas exemplary only, with a true scope being indicated by the followingclaims and their equivalents.

What is claimed is:
 1. A vehicle body, comprising: an internal skeletonfabricated via a first additive manufacturing system; and a skinfabricated in-situ over the internal skeleton via a second additivemanufacturing system that is different from the first additivemanufacturing system.
 2. The vehicle body of claim 1, wherein theinternal skeleton includes a plurality of adjacent hollow tubes.
 3. Thevehicle body of claim 2, wherein: the internal skeleton and the skintogether form a wing shape; and the plurality of adjacent hollow tubesextend in a length direction of the wing shape.
 4. The vehicle body ofclaim 3, wherein the plurality of adjacent hollow tubes are fabricatedfrom a matrix material and a plurality of continuous fibers encasedwithin the matrix material.
 5. The vehicle body of claim 4, wherein theskin is fabricated from a matrix material and a plurality of continuousfibers encased within the matrix material.
 6. The vehicle body of claim5, wherein the plurality of continuous fibers of at least one of theinternal skeleton and the skin are in tension.
 7. The vehicle body ofclaim 5, wherein the plurality of continuous fibers of at least one ofthe internal skeleton and the skin are oriented in a plurality ofdifferent directions.
 8. The vehicle body of claim 5, wherein theplurality of continuous fibers of at least one of the internal skeletonand the skin have trajectories that curve in at least two dimensions. 9.The vehicle body of claim 8, wherein the plurality of continuous fibersare organically arranged within the skin.
 10. The vehicle body of claim9, wherein the plurality of continuous fibers in the skin extend from abase end near a fore/aft center of the wing shape toward a tip end atleading and trailing edges of the wing shape.
 11. The vehicle body ofclaim 10, wherein a density of the plurality of continuous fibers in theskin varies along a length of the wing shape.
 12. The vehicle body ofclaim 11, wherein a density of the plurality of continuous fibers in theskin is greater at the base end than at the tip end.
 13. The vehiclebody of claim 5, wherein the matrix material of both the internalskeleton and the skin includes a UV-cured resin.
 14. The vehicle body ofclaim 5, wherein the plurality of continuous fibers of at least one ofthe internal skeleton and the skin includes at least one of anelectrically conductive wire, a shape memory fiber or a fiber opticcoated with at least one of an insulation layer and a strength-enhancinglayer.
 15. The vehicle body of claim 5, wherein: the internal skeletonand the skin together also form a fuselage shape; and the plurality ofcontinuous fibers in the skin extend from the wing shape into the thefuselage shape.
 16. The vehicle body of claim 5, wherein at least someof the plurality of continuous fibers of the internal skeleton extendinto and form a portion of the skin.
 17. The vehicle body of claim 3,wherein at least one of the plurality of adjacent hollow tubes is coatedto function as at least one of a fuel tank and a fuel passage.
 18. Avehicle body having a wing and a fuselage, comprising: an internalskeleton having a plurality of adjacent hollow tubes extending in alength direction of the wing and being formed from a plurality ofcontinuous fibers coated with a matrix; and a skin having a plurality ofcontinuous fibers coated with a matrix and laid over the internalskeleton, wherein: the plurality of continuous fibers of both theinternal skeleton and the skin are in tension; and at least one of theplurality of adjacent hollow tubes is coated to function as at least oneof a fuel tank and a fuel passage.
 19. A method of fabricating a vehiclebody, comprising: implementing a first additive manufacturing techniqueto fabricate an internal skeleton from continuous fibers coated with amatrix; and implementing a second additive manufacturing technique tofabricate a skin over the internal skeleton from continuous fiberscoated with a matrix.
 20. The method of claim 19, wherein implementingthe first additive manufacturing technique to fabricate the internalskeleton includes implementing the first additive manufacturingtechnique to fabricate a plurality of adjacent hollow tubes.